DOS怎么多任务]ۣۣۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖۖ